1. Field of the Invention
This invention relates to a FRP (Fiber-Reinforced Polymer) composite wrapped grooved-wall lining tubular structure and method of manufacturing.
2. Description of the Related Art
A steel-reinforced concrete structure is commonly used in a building structure. Because steel material is heavy and liable to corrode, many alternative reinforcement materials have been proposed. For example, a composite structural member has been disclosed in U.S. Pat. No. 6,189,286 B1. The composite structural member includes a FRP shell and a concrete core. Ribs are formed on an inner surface of the FRP shell and may be concentric or helical continuing from one end of the fiber-reinforced shell to a desired depth so as to provide a mechanical bond interlock between the fiber-reinforced shell and the concrete core. The FRP shell is made by winding filaments which are pre-coated with resin or polymer binders (i.e., prepreg filaments) on a rotating mandrel, and curing the filaments. After curing, the FRP shell is removed from the rotating mandrel. In order to form the ribs on the inner surface of the FRP shell, the mandrel is formed with a pattern corresponding to the ribs. However, it is difficult to remove the FRP shell from the mandrel due to the presence of the ribs.
In addition, as the filaments are wound about a rotating axis of the mandrel, rather than along a direction of the rotating axis, the composite structural member is relatively weak along the direction of the rotating axis.